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OBGYN.net Conference CoverageFrom American Institute of Ultrasound in MedicineSan Antonio, Texas - March, 1999
Barbara Nesbitt: "Hi, I'm Barbara Nesbitt and I'm here at AIUM with Dr. Barry Schifrin, who's a member of the Fetal Monitoring Editorial Advisory Board at OBGYN.net. We're going to discuss the pitfalls of fetal monitoring. Welcome! I know you have been involved in this since the earliest days of fetal monitoring."
Dr. Barry Schifrin: "'Committed' is a better word..."
Barbara Nesbitt: "'Committed' is better, yes, and I know that you are very interested in the wonderful things that they thought it was going to do. Does it actually do all of that? Of course, it does do wonderful things, but where did they lose some of what they thought it was going to do, and what was that?"
Dr. Barry Schifrin: "I'm not sure they lost some of the things that they thought it was going to do. Clearly, it was introduced in the later part of 1969 and the early 1970s with extraordinary expectations. The expectations were that it would lower the fetal-neonatal mortality, morbidity, and the risk of neurologic injury. They thought that, paradoxically, it would now lower the caesarian section rate because most caesarian sections for fetal distress at the time were based on the stethoscope, and they didn't really correlate with outcomes. So we have not lived up to all of those expectations for a number of reasons, part of which were the expectations themselves."
Barbara Nesbitt: "Tell us a little bit about some of the wonderful things that it does and why it is good to have it."
Dr. Barry Schifrin: "There are several obvious benefits. One is, statistically, it has simply helped lower the death rate during labor so that stillbirth today is virtually unheard of and there are, to my knowledge, no reported cases of an unexpected stillbirth. So before the advent of fetal monitoring, for example, you would be at the bedside, hear a heart rate, and it was not uncommon to go back some time later and all of a sudden the heart rate had disappeared. That has essentially been eliminated. The effect on the caesarian section rate is hotly debated. It's obvious that the more you know about interpreting fetal monitoring, the fewer unnecessary caesarian sections will occur as a result of changes in the heart rate pattern. The final thing has to do with helping babies prevent injury, and that has raised two problems. One, you have to know how injury occurs, and that was a problem because in the early days of fetal monitoring the whole idea was that if I could prevent severe asphyxia in the baby, then we would prevent neurologic injury. That would be nice if asphyxia were the major or significant cause of neurologic injury during labor. Global asphyxia means that the whole baby is asphyxiated and it gets progressively worse and worse and is probably an extremely uncommon cause of injury during labor. A more likely explanation for neurologic problems is that they are obtained not only during labor, but also before, and are transient interferences with blood flow. It is from these transient ischemic events which the baby may recover the ability to survive, on the one hand, but not recover the ability to be free from neurologic injury. So we've had to learn something about how babies get injured to be able to use the monitor appropriately. Having said that, the way the monitor does work beneficially is, one, as I said, it lowers the death rate, and two, it really does something which, in fact, keeps the baby out of harm's way and that is very, very true."
Barbara Nesbitt: "Would this be for cerebral palsy?"
Dr. Barry Schifrin: "Yes, and not only for cerebral palsy, but the risk of death as well. For example, as a general principle, we restrict potentially compromising techniques to the demonstratively normal baby. So before you give oxytocin or use an epidural, and before you even begin to think about an induction of labor, you ask yourself, 'is the baby all right or do I have to do something for the baby before I consider these other things?' That's what monitoring does best - it keeps you from beginning a course of action, such as induction or augmentation of labor, and it restricts those activities to essentially the demonstratively normal baby. This is the thing that the monitor does best, and it does it better than anything else that exists. In terms of the definition of normal, by 'normal' I mean not only the baby who has no problem with oxygenation, but also the baby who is almost certainly neurologically normal because the heart rate pattern - not the heart rate, but the heart rate pattern - is the end organ for not only the heart, but the brain as well."
Barbara Nesbitt: "Let's say you have a woman comes in to the labor and delivery room, she's put on the fetal monitor, and she gets an epidural. I think there's a lot of controversy about epidurals, and I think we all know that if they're given too early there is a problem. I was trained so that if it was at 5 cm, then it was all right. So if somebody did have a problem, the fetal monitor was going to pick that up, right?"
Dr. Barry Schifrin: "It will pick up a problem if there is one before the epidural, and tell us 'maybe you should not give this epidural, which has potential complications of its own.' Depending upon how the epidural is given and how much lowering of the blood pressure may occur in response, the baby will respond. It is unheard of that a baby who is becoming hypoxic or suffering from diminished blood flow will not fail to respond. There's no evidence of that. If there's a problem with fetal monitoring in terms of its pitfalls, it's that there are too many abnormal heart rate patterns and not all of them signify significant problems in the baby. The baby simply has too many resources in terms of what it can do with its heart rate to scare you, and it is an understanding of what is significant and what is not that relates to the education about fetal monitoring. But the issue of labor is separate, you see, from the issue of the appropriateness of epidural at a certain amount of progress in labor, and a certain amount of uterine activity..."
Barbara Nesbitt: "That's for the mother?"
Dr. Barry Schifrin: "That's for the mother and that's for the labor. Remember, the fetal monitor is only asking one and a half questions. It says 'you see this contraction? How did you like that one?,' and then it goes to the next contraction and asks the baby how it likes that one, and so that is the way it works. It simply goes from contraction to contraction and asks, 'for this number of contractions, for this frequency and aptitude of contractions, how are you doing?' It doesn't tell you whether it's a good idea or not a good idea to do an epidural, other than the baby is okay and tolerating the amount of stress that this amount of uterine contractions have depressed upon it."
Barbara Nesbitt: "So the fetal monitor treats the fetus and the…"
Dr. Barry Schifrin: "It doesn't treat."
Barbara Nesbitt: "But I mean, it's monitoring the unborn child, where the epidural is for comfort for both the mother…"
Dr. Barry Schifrin: "But that's an obstetrical consideration, as opposed to a fetal consideration. Remember, with the fetal monitor, what we are doing is taking information - essentially end organ response information - directly from the fetus itself, and that is the great virtue of what it is. It is not a secondary or indirect parameter. It is, in fact, a primary."
Barbara Nesbitt: "You mentioned something about the ABCs of fetal monitoring. Tell us about this."
Dr. Barry Schifrin: "The A is not from ABC, the way I refer to it, and it is not meant to be referred to any basic notion of monitoring or even the beginning of the alphabet or something as simple as that. The A stands for asphyxia, anaerobia, hypoxia, and what have you. The B stands for behavior, or what we're able to see on the fetal monitor and the fetal monitor patterns in which we are able to understand fetal behavioral patterns. The C is for the courage to believe A and B. Babies, for example, can not be asphyxiated but have abnormal behavior even to the point of injury or anomaly without being asphyxiated. Babies can be hypoxic but have their nervous systems still working and compensating for that without injury. The way you need to evaluate a pattern is from those two different perspectives. Do I have a baby where there is a potential problem with oxygen, and do I have a baby where there is a potential problem with its neurologic control over its heart rate? Those are two independent questions that cannot be answered by any single parameter. They can't be answered by counting how many accelerations you have or by measuring how big of an acceleration you have. They can't be answered by figuring out how long they are, or simply by discerning how much variability you have. What you need to do is to take both classes of information and synthesize them to understand the question, 'how are you doing?' Before the advent of fetal monitoring, that was not possible. The use of the stethoscope was never designed to determine how the baby was doing. At its best incarnation, it was only designed to be able to tell whether you had to intervene or not, or whether it was necessary…"
Barbara Nesbitt: "Whether there was a heart beat to hear?"
Dr. Barry Schifrin: "Whether there was a problem or not, and whether to intervene. That's very different from fetal monitoring. Fetal monitoring is here to tell you - if you look at it properly - if you are doing all right, if you are behaving yourself, if you are getting enough oxygen, and parenthetically, if you have a burning desire to be someplace else. These are questions for which the monitor is reasonably, but not infallibly, suited to answer."
Barbara Nesbitt: "So the monitor is there to see if you have any problems at all. A woman goes in to have a baby, finds she has no problems at all, but the monitor is there in case she has them. Sometimes they might say, 'I don't know why I needed one, I never had any problems.' But the monitor is there to pick up the case that happens where nobody would have been able to do anything about it quicker."
Dr. Barry Schifrin: "We've come to find that there are lots of things that you can do, but you can't always prevent injury. This is what monitoring has helped us understand. It has helped us understand that injury sometimes occurs so rapidly that with a knife in your hand and a patient with a previously normal tracing on the table, you would not be able to get the baby out intact soon enough, even under those circumstances. Sometimes it happens very quickly, and that is why one of the original pitfalls of monitoring had to do with this notion of rescue, that a baby would have these decelerations and we would rescue it. The fact is, sometimes you need to do that if some catastrophic event occurs, but the notion of being able to rescue, or being able to get in there soon enough to prevent injury under any and all circumstances, is not a reasonable one. The monitors' great role is not to essentially affect rescue, but to keep the babies out of harm's way in the beginning."
Barbara Nesbitt: "Very good. Thank you very much, doctor. Do you have anything else you'd like to add?"
Dr. Barry Schifrin: "Just to say thank you for the opportunity, and I'm happy to be aboard."
Barbara Nesbitt: "Thank you, and welcome to OBGYN.net."
Dr. Barry Schifrin: "Thank you."